PEORIA, ILLINOIS

Plant Polymer Res., USDA, ARS, NCAUR

New zein genes mapped to chromosome 7 by IEF and HPLC

--C. M. Wilson

A number of zein genes have been mapped to chromosomes 4 and 7 by determining linkages using IEF in agarose (C. M. Wilson, Theor. Appl. Genet. 77:217, 1989). The genes on chromosome 7 were identified as Zp B9/22, Zp B9/10, and Zp B8/38, where the first nomenclature element refers to SDS-PAGE and the second to the IEF position. Zp B9/21, found only in R801, W22, and H55, was thought to be on chromosome 7. R801 was pollinated by WF9 or Oh45, which have Zp B9/10 and Zp B9/22 with genes on chromosome 7. The F1 was pollinated by B57 or by W64A, inbreds which have only Zp B9/38 mapped to chromosome 7. The resultant seeds were assayed by IEF for the presence or absence of IEF bands 10, 21, and 22. For the cross (WF9xR801)xB57, 34 seeds had bands 10 and 22, while 30 had band 21. For (Oh45xR801)xW64A, 59 seeds had bands 10 and 22, while 60 had band 21. The conclusion is that genes for these three zeins are closely linked at the same position on chromosome 7, with IEF band 21 being in repulsion to bands 10 and 22.

Serial analysis by reversed-phase high pressure liquid chromatography (HPLC) in addition to IEF and SDS-PAGE identifies more zeins than can be found by IEF alone (C. M. Wilson, Plant Physiol. in press). IEF band 38 produces two bands on HPLC, but the linkage experiments (TAG 77:217, 1989) suggest that the genes for the two band 38 zeins are tightly linked on chromosome 7. IEF band 21 from R801 elutes from the HPLC column at the same time as the second IEF band 38 from inbreds B57, W64A, and N28. These results show that no single assay for separation of zein polypeptides can give unique identifications to the many zeins in a single inbred.

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